PB1932: RETROSPECTIVE STUDY OF BURDEN OF INFECTION IN PATIENTS WITH AND WITHOUT SECONDARY IMMUNODEFICIENCY DISEASE FOLLOWING DIAGNOSIS OF CHRONIC LYMPHOCYTIC LEUKAEMIA
Authors: Matthew Davids, Joshua Richter, Colin Anderson-Smits, Marta Kamieniak, Kaili Ren, Drishti Shah, Csaba Siffel
Journal: HemaSphere (2023)

Topic: 6. Chronic lymphocytic leukemia and related disorders - Clinical Background: Patients with lymphoid malignancies such as chronic lymphocytic leukaemia (CLL)/small lymphocytic lymphoma (SLL) are at risk of developing secondary immunodeficiency disease (SID) owing to the underlying disease process and immunosuppressive treatments. Patients with SID are susceptible to severe, recurrent or persistent infections that can result in reduced quality of life and a substantial clinical and economic burden. Aims: To evaluate burden of infection in patients with and without SID following diagnosis of CLL/SLL. Methods: This observational, retrospective cohort study was conducted using anonymized data from the Optum-Humedica database in the USA (1 October 2015–10 March 2020). Patients with SID (SID cohort) and without SID (no-SID cohort) were identified 1 April 2016–10 March 2019 (the selection window). The definition of SID included International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) hypogammaglobulinaemia codes, low immunoglobulin G (IgG) levels (< 5.0 g/L) and signs/symptoms of SID. The SID index date was the earliest occurrence of an ICD-10-CM hypogammaglobulinaemia code or record of low IgG levels. In patients without SID, the index date was randomly assigned to replicate the distribution of index dates in the SID cohort. CLL/SLL diagnosis and baseline characteristics were identified during a 6-month pre-index period. Included patients were aged ≥ 18 years, with a confirmed diagnosis of CLL/SLL and clinical activity for ≥ 6 months prior to and ≥ 3 months following the index date. Infection-related outcomes and treatment patterns were assessed in patients with ≥ 12-month follow-up post-index date. Overall survival was measured in patients with ≥ 3 months follow-up post-index date. Results: Of patients with CLL/SLL, 502 and 3928 with and without SID, respectively, were included with ≥ 12 months follow-up (SID vs no-SID: mean [standard deviation; SD] age 70.6 [9.7] vs 71.6 [10.5] years; 59.2% vs 57.7% male). At 12-month follow-up, a larger proportion of patients with SID had ≥ 1 infection than those without SID (SID: 70.1%; no-SID: 30.4%; p < 0.001). Compared with the no-SID cohort, in the SID cohort there was also a higher number of infections (SID vs no-SID: mean [SD]: 8.4 [12.7] vs 4.1 [5.4]; p < 0.001), proportion of patients with ≥ 1 SBI (SID: 39.8%; no-SID: 9.2%; p < 0.001) and proportion of patients with ≥ 1 infection-associated hospitalization (SID: 27.7%; no-SID: 5.8%; p < 0.001). The most common type of infection was bacterial (SID: 63.7%; no-SID: 24.9%); in those patients who experienced an SBI, the most frequently reported infection was bacterial pneumonia (SID: 85.5% patients with SBI; no-SID: 72.9% patients with SBI). A larger proportion of patients with SID received anti-infectives than patients without SID (SID: 85.5%; no-SID: 48.6%; p < 0.001), the most common type in both cohorts being antibiotics (SID: 83.1%; no-SID: 45.6%). To assess overall survival, 646 and 4719 patients with and without SID, respectively, were included. Overall survival at 24 months was lower in the SID cohort than the no-SID cohort (SID: 77.3%; no-SID: 87.2%). Summary/Conclusion: Patients with CLL/SLL who subsequently developed SID had a greater burden of infection than patients who did not develop SID. Increasing understanding of this burden of infection may help to improve outcomes in this population. Takeda Development Center Americas, Inc. funded this study. Takeda Pharmaceuticals International AG funded writing support. Keywords: Chronic lymphocytic leukemia, Immunoglobulin